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What is the Periodic Table Showing? Periodicity

The INTERNET Database of Periodic Tables

There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).

   Use the drop menus or search box (below) to Select or Search the 1400 entries in the database: 

  Or, Search by Text String:       

Elements by Name:

1902   Actinium, Discovery of
2025   Actinium: The Most Annoying Element for the Rare-Earth Industry?
1825   Aluminium (Aluminum), Discovery of
1944   Americium, Discovery of
1858   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1858
1859   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1859
1860   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1860
1861   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1861
1862   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1862
1863   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1863
1864   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1864
1865   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1865
1866   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1866
1867   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1867
1868   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1868
1869   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1869
1870   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1870
1871   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1871
1872   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1872
1873   Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1873
800 BCE   Antimony, Discovery of
1894   Argon, Discovery of
300 BCE   Arsenic, Discovery of
1940   Astatine, Discovery of
1808   Barium, Discovery of
1949   Berkelium, Discovery of
1798   Beryllium, Discovery of
1753   Bismuth, Discovery of
1981   Bohrium, Discovery of
1808   Boron, Discovery of
1825   Bromine, Discovery of
1817   Cadmium, Discovery of
1808   Calcium, Discovery of
1950   Californium, Discovery of
1858   Cannizzaro's Letter or Sunto
3750 BCE   Carbon, Discovery of
1803   Cerium, Discovery of
1860   Cesium, Discovery of
1774   Chlorine, Discovery of
1798   Chromium, Discovery of
1735   Cobalt, Discovery of
1996   Copernicium, Discovery of
9000 BCE   Copper, Discovery of
1944   Curium, Discovery of
1829   Döbereiner's Triads
1808   Dalton's Elements
1803   Dalton's Postulates About The Elements
1994   Darmstadtium, Discovery of
1831   Daubeny's Teaching Display Board & Wooden Cubes of Atomic Weights
1970   Dubnium, Discovery of
1886   Dysprosium, Discovery of
1952   Einsteinium, Discovery of
1955   Element Hunters
2023   Element Names: The Etymology of The Periodic Table
1000   Elements Known in the Year 1000
1700   Elements Known in the Year 1700
1800   Elements Known in The Year 1800
1850   Elements Known in the Year 1850
1900   Elements Known in The Year 1900
1950   Elements Known in the Year 1950
2000   Elements Known in the Year 2000
2011   Elements Known in the Year 2011
1842   Erbium, Discovery of
1901   Europium, Discovery of
1952   Fermium, Discovery of
1999   Flerovium, Discovery of
1886   Fluorine, Discovery of
1939   Francium, Discovery of
1880   Gadolinium, Discovery of
1875   Gallium, Discovery of
1886   Germanium, Discovery of
6000 BCE   Gold, Discovery of
1922   Hafnium, Discovery of
1984   Hassium, Discovery of
1895   Helium, Discovery of
1900   History of the Discovery of the Group 18 (erstwhile Group 0) Elements
2021   History [of the] Elements and Periodic Table
1879   Holmium, Discovery of
1766   Hydrogen, Discovery of
1863   Indium, Discovery of
1811   Iodine, Discovery of
1803   Iridium, Discovery of
5000 BCE   Iron, Discovery of
1898   Krypton, Discovery of
1838   Lanthanum, Discovery of
1961   Lawrencium, Discovery of
7000 BCE   Lead, Discovery of
1817   Lithium, Discovery of
2000   Livermorium, Discovery of
1906   Lutetium, Discovery of
1808   Magnesium, Discovery of
1774   Manganese, Discovery of
1982   Meitnerium, Discovery of
1955   Mendelevium, Discovery of
2000 BCE   Mercury, Discovery of
1781   Molybdenum, Discovery of
2003   Moscovium, Discovery of
1913   Moseley's Periodic Law
1885   Neodymium, Discovery of
1898   Neon, Discovery of
1940   Neptunium, Discovery of
1751   Nickel, Discovery of
2003   Nihonium, Discovery of
1801   Niobium, Discovery of
1772   Nitrogen, Discovery of
1966   Nobelium, Discovery of
2002   Oganesson, Discovery of
1803   Osmium, Discovery of
1771   Oxygen, Discovery of
1803   Palladium, Discovery of
2019   Periodic Table of the Elements Coloring Book
1669   Phosphorus, Discovery of
1748   Platinum, Discovery of
1940   Plutonium, Discovery of
1898   Polonium, Discovery of
1807   Potassium, Discovery of
1885   Praseodymium, Discovery of
1945   Promethium, Discovery of
1913   Protactinium, Discovery of
1898   Radium, Discovery of
1899   Radon, Discovery of
1919   Rhenium, Discovery of
1804   Rhodium, Discovery of
1994   Roentgenium, Discovery of
1861   Rubidium, Discovery of
1844   Ruthenium, Discovery of
1969   Rutherfordium, Discovery of
1879   Samarium, Discovery of
1879   Scandium, Discovery of
1974   Seaborgium, Discovery of
1817   Selenium, Discovery of
2023   Semicircular Hybrid Chart of the Nuclides
1824   Silicon, Discovery of
5000 BCE   Silver, Discovery of
1807   Sodium, Discovery of
1808   Strontium, Discovery of
2000 BCE   Sulfur (Sulphur), Discovery of
1802   Tantalum, Discovery of
1937   Technetium, Discovery of
1782   Tellurium, Discovery of
2010   Tennessine, Discovery of
1842   Terbium, Discovery of
1861   Thallium, Discovery of
1907   Thompson's Electron Rings
1829   Thorium, Discovery of
1879   Thulium, Discovery of
3500 BCE   Tin, Discovery of
1791   Titanium, Discovery of
1783   Tungsten, Discovery of
1789   Uranium, Discovery of
1830   Vanadium, Discovery of
2022   Which Element is the Best?
1813   Wollaston's Synoptic Scale of Chemical Equivalents
1898   Xenon, Discovery of
1878   Ytterbium, Discovery of
1794   Yttrium, Discovery of
1000 BCE   Zinc, Discovery of
1789   Zirconium, Discovery of
Year:  1902 PT id = 869, Type = element

Discovery of Actinium

Ac

Actinium, atomic number 89, has a mass of 227 au.

Radioactive element.

Actinium was first isolated in 1902 by F. O. Giesel.

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Year:  2025 PT id = 1345, Type = element

Actinium: The Most Annoying Element for the Rare-Earth Industry?

Koen Binnemans writing on Linkedin:

Actinium: The Most Annoying Element for the Rare Earth Industry?

Rare-earth elements (REEs) are often accompanied by radioactive uranium and thorium in their ores. This is particularly problematic for monazite, which can contain more than 15 wt% thorium dioxide. The REE mineral steenstrupine, which occurs in large quantities in Greenland, is so rich in uranium that it can even be mined as a uranium ore. Due to strict safety regulations governing the handling of naturally occurring radioactive materials (NORM), the thorium content of REE ores poses major challenges for REE producers. Thorium is treated as radioactive waste, and its disposal can be very expensive.

It is important to realize that most radioactivity issues are not caused directly by thorium or uranium themselves, since their primary isotopes (thorium-232, uranium-235, and uranium-238) are all very long?lived, but by their radioactive daughter nuclides formed through decay chains.

Most of these radioactive daughter elements have chemical properties sufficiently different from those of the REEs that they can be removed using conventional hydrometallurgical techniques.

However, actinium presents a particular challenge because its chemical properties are similar to those of the REEs, especially lanthanum. The isotope actinium-227, formed by the decay of uranium-235, has a half-life of 22 years. During REE separation, actinium tends to follow lanthanum. In a solvent-extraction circuit, actinium accumulates in the SX battery along with the lanthanum stream.

Although the concentration of actinium is usually very low, lanthanum must be purified as thoroughly as possible, because one important application of lanthanum is in scintillator detectors for ionizing radiation (e.g. (LaBr3:Ce3+ or LaCl3:Ce3+). If lanthanum is contaminated with radioactive actinium, the resulting detector will exhibit significant background noise and therefore poor performance. Another issue is that REE concentrates produced at mining sites may exceed legal radioactivity limits for export to REE refineries due to the presence of actinium.

Therefore, REE processing companies have developed processes to remove actinium from REE concentrates or feed solutions for SX operations. Limited information is available in the scientific literature, but more can be found in patent documents. For instance, read the following patent of CARESTER, https://lnkd.in/evXsXzDB

It should also be noted that actinium has useful applications: actinium?225 is used in radiopharmaceuticals for the precision treatment of tumors. See: PANTERA

SOLVOMET R&I Centre SIM2 KU Leuven

Oak Ridge National Laboratory (Wikipedia) Blue Cerenkov radiation emitted by a sample of actinium-225

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Year:  1825 PT id = 792, Type = element

Discovery of Aluminium (Aluminum)

Al

Aluminium (aluminum), atomic number 13, has a mass of 26.982 au.

Aluminum is a silvery-white metal.

Aluminium was first isolated in 1825 by H.C.Ørsted.

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Year:  1944 PT id = 875, Type = element

Discovery of Americium

Am

Americium, atomic number 95, has a mass of 243 au.

Synthetic radioactive element. It is used in smoke detectors, and so – surprisingly – is present most houses and buildings.

Americium was first observed in 1944 by G. T. Seaborg, R. A. James, O. Morgan and A. Ghiorso.

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Year:  1858 PT id = 1348, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1858

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1858 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1859 PT id = 1349, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1859

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1859 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1860 PT id = 1350, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1860

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1860 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1861 PT id = 1351, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1861

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1861 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1862 PT id = 1352, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1862

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1862 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1863 PT id = 1353, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1863

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1863 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1864 PT id = 1354, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1864

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1864 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1865 PT id = 1355, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1865

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1865 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1866 PT id = 1356, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1866

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1866 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1867 PT id = 1357, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1867

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1867 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

 

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1868 PT id = 1358, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1868

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1868 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

 

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1869 PT id = 1359, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1869

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1869 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

 

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1870 PT id = 1360, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1870

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1870 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1871 PT id = 1361, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1871

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1871 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1872 PT id = 1362, Type = formulation element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1872

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1872 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Thanks to René and Mario Rodriguez for the tip!

Top of Page
Year:  1873 PT id = 1363, Type = formulation review element weight

Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1873

Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.

The 1873 table of data is here.

Mark Leach writes:

"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systematic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.

"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."

Notes:

Thanks to René and Mario Rodriguez for the tip!

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Year:  800 BCE PT id = 831, Type = element

Discovery of Antimony

Sb

Antimony, atomic number 51, has a mass of 121.76 au.

Antimony had its earliest use in about 800 BCE.

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Year:  1894 PT id = 797, Type = element

Discovery of Argon

Ar

Argon, atomic number 18, has a mass of 39.948 au.

Argon is a noble gas.

Argon was first isolated in 1894 by Lord Rayleigh and W. Ramsay.

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Year:  300 BCE PT id = 813, Type = element

Discovery of Arsenic

As

Arsenic, atomic number 33, has a mass of 74.922 au.

Arsenic had its earliest use in about 300 BCE.

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Year:  1940 PT id = 865, Type = element

Discovery of Astatine

At

Astatine, atomic number 85, has a mass of 210 au.

Radioactive element.

Astatine was first observed or predicted in 1940 by R. Corson, R. MacKenzie and E. Segrè.

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Year:  1808 PT id = 836, Type = element

Discovery of Barium

Ba

Barium, atomic number 56, has a mass of 137.327 au.

Barium is a Group 2 element, and these are called: "alkaline earth metals".

Barium was first observed or predicted in 1772 by W. Scheele and first isolated in 1808 by H. Davy.

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Year:  1949 PT id = 877, Type = element

Discovery of Berkelium

Bk

Berkelium, atomic number 97, has a mass of 247 au.

Synthetic radioactive element.

Berkelium was first observed in 1949 by G. Thompson, A. Ghiorso and G. T. Seaborg.

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Year:  1798 PT id = 784, Type = element

Discovery of Beryllium

Be

Beryllium, atomic number 4, has a mass of 9.012 au.

Beryllium is a metal with a high melting point. At ordinary temperatures it resists oxidation in air. Beryllium compounds are very toxic.

Beryllium was first observed or predicted in 1798 by N. Vauquelin and first isolated in 1828 by F. Wöhler and A. Bussy.

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Year:  1753 PT id = 863, Type = element

Discovery of Bismuth

Bi

Bismuth, atomic number 83, has a mass of 208.98 au.

Bismuth was first isolated in 1753 by C.F. Geoffroy.

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Year:  1981 PT id = 887, Type = element

Discovery of Bohrium

Bh

Bohrium, atomic number 107, has a mass of 272 au.

Synthetic radioactive element.

Bohrium was first observed in 1981 by G.Münzenberget al.

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Year:  1808 PT id = 785, Type = element

Discovery of Boron

B

Boron, atomic number 5, has a mass of 10.814 au.

Boron has properties that are borderline between metal and non-metal (semimetallic).

Boron was first observed or predicted in 1808 by L. Gay-Lussac and L.J. Thénard and first isolated in 1808 by H. Davy.

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Year:  1825 PT id = 815, Type = element

Discovery of Bromine

Br

Bromine, atomic number 35, has a mass of 79.904 au.

Bromine exists as an orange diatomic molecular liquid, Br2.

Bromine was first isolated in 1825 by J. Balard and C. Löwig.

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Year:  1817 PT id = 828, Type = element

Discovery of Cadmium

Cd

Cadmium, atomic number 48, has a mass of 112.414 au.

Cadmium was first isolated in 1817 by S. L Hermann, F. Stromeyer and J.C.H. Roloff.

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Year:  1808 PT id = 800, Type = element

Discovery of Calcium

Ca

Calcium, atomic number 20, has a mass of 40.078 au.

Calcium is a Group 2 element, and these are called: "alkaline earth metals".

Calcium was first isolated in 1808 by H. Davy.

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Year:  1950 PT id = 878, Type = element

Discovery of Californium

Cf

Californium, atomic number 98, has a mass of 251 au.

Synthetic radioactive element.

Californium was first observed in 1950 by S. G. Thompson, K. Street, Jr., A. Ghiorso and G. T. Seaborg.

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Year:  1858 PT id = 1047, Type = formulation review element weight structure

Cannizzaro's Letter or Sunto

Letter of Professor Stanislao Cannizzaro to Professor S. De Luca: Sunto di un corso di filosofia chimica (Sketch of a Course of Chemical Philosophy) given in the Royal University of Genoa, Il Nuovo Cimento, vol. vii. (1858), pp. 321-366.

Many thanks to Carmen Giunta, Professor of Chemistry Emeritus, Le Moyne College who provided the information about, and link to, Cannizzaro's Letter. See a list of other classic chemistry papers.

Read the full letter/paper, in English translation, here. (The Italian version is here.)

Cannizzaro writes:

"I believe that the progress of science made in these last years has confirmed the hypothesis of Avogadro, of Ampère, and of Dumas on the similar constitution of substances in the gaseous state; that is, that equal volumes of these substances, whether simple or compound, contain an equal number of molecules: not however an equal number of atoms, since the molecules of the different substances, or those of the same substance in its different states, may contain a different number of atoms, whether of the same or of diverse nature."

From the Science History of Science Institute:

"In 1858 Cannizzaro outlined a course in theoretical chemistry for students at the University of Genoa,where he had to teach without benefit of a laboratory. He used the hypothesis of a fellow Italian, Amedeo Avogadro, who had died just two years earlier, as a pathway out of the confusion rampant among chemists about atomic weights and the fundamental structure of chemical compounds."

Mark Leach writes:

"Before a periodic table of the chemical elements – which orders the elements by atomic weight and then groups them by property – could be developed it was necessary to know the atomic weight values. However, to deduce the atomic weights was a problem as it was necessary to know the ratios of how the elements combined, the stoichiometry.

"Tables of atomic weight data by Dalton (1808), Wollaston (1813), Daubeny (1831) and Kopp & Will (1858) show progress, but the 1858 Cannizzaro letter was the first where the atomic weight data is more or less both complete and accurate, thus removing stiochiometric errors.

"I have extracted the element atomic weight data from the paper, and given the % error with respect to modern atomic weight/mass data. Only titanium is significantly out! It is clear that Cannizzaron knew that hydrogen, nitrogen, oxygen, chlorine, bromine & iodine existed as diatomic molecules."

Element Symbol Cannizzaro's Weight Modern Weight/Mass % error
Hydrogen H 1 1.008 -0.8%
Boron B 11 10.81 1.7%
Carbon C 12 12.011 -0.1%
Nitrogen N 14 14.007 0.0%
Oxygen O 16 15.999 0.0%
Sodium Na 23 22.99 0.0%
Magnesium Mg 24 24.305 -1.3%
Aluminium Al 27 26.982 0.1%
Silicon Si 28 28.085 -0.3%
Sulphur S 32 32.06 -0.2%
Phosphorus P 32 30.974 3.2%
Chlorine Cl 35.5 35.45 0.1%
Potassium K 39 39.098 -0.3%
Calcium Ca 40 40.078 -0.2%
Chromium Cr 53 51.996 1.9%
Manganese Mn 55 54.938 0.1%
Iron Fe 56 55.845 0.3%
Titanium Ti 56 47.867 14.5%
Copper Cu 63 63.546 -0.9%
Zinc Zn 66 65.38 0.9%
Arsenic As 75 74.922 0.1%
Bromine Br 80 79.904 0.1%
Zirconium Zr 89 91.224 -2.5%
Silver Ag 108 107.87 0.1%
Tin Sn 117.6 118.71 -0.9%
Iodine I 127 126.9 0.1%
Barium Ba 137 137.3 -0.2%
Platinum Pt 197 195.08 1.0%
Mercury Hg 200 200.59 -0.3%
Lead Pb 207 207.2 -0.1%
Diatomic Molecule Formula Cannizzaro's Weight Modern Weight/Mass % error
Hydrogen H2 2 2.016 -0.8%
Oxygen O2 32 31.998 0.0%
Sulphur S2 64 64.12 -0.2%
Chlorine Cl2 71 70.9 0.1%
Bromine Br2 160 159.808 0.1%
Iodine I2 254 253.8 0.1%
Molecule Formula Cannizzaro's Weight Modern Weight/Mass % error
Water H2O 18 18.015 -0.1%
Hydrochloric Acid HCl 36.5 36.458 0.1%
Methane CH4 16 16.043 -0.3%
Hydrogen sulphide H2S 34 34.076 -0.2%
Diethyl ether CH3CH2OCH2CH3 74 74.123 -0.2%
Carbon disulphide CS2 76 76.131 -0.2%
Chloroethane CH3CH2Cl 64.5 64.512 0.0%

Below is a list of the elements showing which ones were included by Cannizzaro and which one were ommitted (because they had not been discovered) or are strangely missing. Odd ommissions (to the modern eye) include: Lithium, Beryllium, Cobalt, Nickel, Palladium, Tungsten and Gold.

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Year:  3750 BCE PT id = 786, Type = element

Discovery of Carbon

C

Carbon, atomic number 6, has a mass of 12.011 au.

Carbon has many allotropes, including: graphite, diamond, graphene, C60, single wall nanotubes, etc.

Carbon had its earliest use in about 3750 BCE. It was discovered by Egyptians and Sumerians.

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Year:  1803 PT id = 838, Type = element

Discovery of Cerium

Ce

Cerium, atomic number 58, has a mass of 140.116 au.

Cerium was first observed or predicted in 1803 by H. Klaproth, J. Berzelius, and W. Hisinger and first isolated in 1838 by G. Mosander.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1860 PT id = 835, Type = element

Discovery of Cesium

Cs

Cesium (or caesium), atomic number 55, has a mass of 132.905 au.

Cesium is a Group 1 element, and these are often referred to as the "alkali metals".

Cesium was first observed or predicted in 1860 by R. Bunsen and R. Kirchhoff and first isolated in 1882 by C. Setterberg.

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Year:  1774 PT id = 796, Type = element

Discovery of Chlorine

Cl

Chlorine, atomic number 17, has a mass of 35.452 au.

Chlorine exists as a green diatomic molecular gas, Cl2.

Chlorine was first isolated in 1774 by W. Scheele.

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Year:  1798 PT id = 804, Type = element

Discovery of Chromium

Cr

Chromium, atomic number 24, has a mass of 51.996 au.

Chromium was first observed or predicted in 1797 by N. Vauquelin and first isolated in 1798 by N. Vauquelin.

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Year:  1735 PT id = 807, Type = element

Discovery of Cobalt

Co

Cobalt, atomic number 27, has a mass of 58.933 au.

Cobalt was first isolated in 1735 by G. Brandt.

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Year:  1996 PT id = 892, Type = element

Discovery of Copernicium

Cn

Copernicum, atomic number 112, has a mass of 285 au.

Synthetic radioactive element.

Copernicium was first observed in 1996 by S. Hofmann et al.

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Year:  9000 BCE PT id = 809, Type = element

Discovery of Copper

Cu

Copper, atomic number 29, has a mass of 63.546 au.

Copper had its earliest use in about 9000 BCE, and the oldest sample dates from 6000 BCE. It was discovered by Middle East workers and the earliest sample is from Anatolia.

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Year:  1944 PT id = 876, Type = element

Discovery of Curium

Cm

Curium, atomic number 96, has a mass of 247 au.

Synthetic radioactive element.

Curium was first observed in 1944 by G. T. Seaborg, R. A. James and A. Ghiorso.

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Year:  1829 PT id = 6, Type = formulation element

Döbereiner's Triads

Johann Döbereiner found triads: a sequence of three similar elements, where the middle element has a mass equal to the average of the least and most massive.

A brief biography can be found on the Nature website.

Döbereiner writes in An Attempt to Group Elementary Substances according to Their Analogies (in English)

From Poggendorf's Annalen der Physik und Chemie 15, 301-7 (1829) (in German) [from Henry M. Leicester & Herbert S. Klickstein, eds., A Source Book in Chemistry, 1400-1900 (Cambridge, MA: Harvard, 1952)]:

"The work of Berzelius on the determination of the atomic weights of bromine and iodine has interested me greatly, since it has established the idea, which I expressed earlier in my lectures, that perhaps the atomic weight of bromine might be the arithmetical mean of the atomic weights of chlorine and iodine. This mean is (35.470+126.470)/2 = 80.470. This number is not much greater than that found by Berzelius (78.383); however, it comes so close that it may almost be hoped that the difference will vanish entirely after repeated careful and exact determinations of the atomic weights of these three salt-forming elements. This idea was the motive for an attempt which I made twelve years ago to group substances by their analogies."

[Note: L&K noticed an error in the above math: (35.47 + 126.47)/2 = 80.97 not 80.47. Whoops...]

The diagram below uses mid-nineteenth century atomic mass information rather than modern data. If atomic numbers (Z) are used (a property unknown in 1850), the triads are exact:

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Year:  1808 PT id = 5, Type = formulation data element weight structure

Dalton's Elements

Two pages from John Dalton's A New System of Chemical Philosophy in which he proposed his version of atomic theory based on scientific experimentation (see the scanned book, page 219):

Name Modern Symbol Dalton's Data Modern Values % error
Hydrog. H 1 1 0%
Azote N 5 14 -180%
Carbone C 5 12 -140%
Oxygen O 7 16 -129%
Phosphorus P 9 31 -244%
Sulphur S 13 32.1 -147%
Magnesia Mg 20 24.3 -22%
Lime Ca 24 40.1 -67%
Soda Na 28 23 18%
Potash K 42 39.1 7%
Strontites Sr 46 87.6 -90%
Barytes Ba 68 137.3 -102%
Iron Fe 50 55.8 -12%
Zinc Zn 56 65.4 -17%
Copper Cu 56 63.5 -13%
Lead Pb 90 200.6 -123%
Silver Ag 190 107.9 43%
Gold Au 190 197 -4%
Platina Pt 190 195.1 -3%
Mercury Hg 167 200.6 -20%

By Mark Leach

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Year:  1803 PT id = 4, Type = formulation element weight structure

Dalton's Postulates About The Elements

Around the year 1803 in Manchester, John Dalton gave a series of lectures in which he presented his postulates:

From a very early notebook from around this time:

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Year:  1994 PT id = 890, Type = element

Discovery of Darmstadtium

Ds

Darmstadtium, atomic number 110, has a mass of 281 au.

Synthetic radioactive element.

Darmstadtium was first observed in 1994 by S. Hofmann et al.

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Year:  1831 PT id = 337, Type = formulation element weight

Daubeny's Teaching Display Board & Wooden Cubes of Atomic Weights

The Museum of the History of Science, Oxford, has a display of Charles Daubeny's teaching materials, including a black painted wooden board with "SYMBOLS OF SIMPLE BODIES": showing symbols, atomic weights and names of elements in two columns, and a small pile of cubes with element symbols.

Charles Daubeny and Chemistry at the Old Ashmolean

Charles Daubeny (1795-1867) was appointed Aldrichian Professor of Chemistry at Oxford in 1822. In 1847 he moved from the original laboratory in this basement [in the museum] to a new one built at his own expense at the Botanic Garden. His apparatus went with him and was preserved there. Daubeny actively campaigned for the teaching of science in Oxford and held several professorships in addition to chemistry. He also conducted research on subjects such as photosynthesis.

From the HSM Database (Inventory no. 17504):

DAUBENY'S LIST OF ATOMIC WEIGHTS Wooden panel, black with white lettering, listing in two columns the symbols and names of twenty elements. This lecture board is identical to the table in the third edition (1831) of E. Turner, 'Elements of Chemistry', apart from the atomic weight for bromine. Daubeny wrote a useful 'Introduction to the Atomic Theory' (published in three versions: 1831, 1840, and 1850), the first edition of which also quotes Turner's table. Probably contemporary with this lecture board are the wooden cubes with the symbols for certain elements.

The period from 1810 to 1860 was crucial in the development of the periodic table. Most of the main group and transition elements had been discovered, but their atomic weights and stoichiometries (combining ratios) had not been fully deduced. Oxygen was assumed to have a weight of 6, and consequently carbon is assumed to have a mass of 6.

Daubeny's element symbols and weights – along with the modern mass data – are tabulated:

Symbol Daubeny's Weight Modern Mass Data % error Stoichiometry Error
H 1 1 0%  
C 6 12 -100% factor of 2
O 8 16 -100% factor of 2
Si 8 28.1 -251% factor of 5 (?)
Al 10 27 -170% factor of 3
Mg 12 24.3 -103% factor of 2
N 14 14 0%  
S 16 32.1 -101% factor of 2
P 16 31 -94% factor of 2
Fl 19 19 0%  
Ca 20 40.1 -101% factor of 2
Na 24 23 4%  
Fe 28 55.8 -99% factor of 2
Cl 36 35.5 1%  
K 40 39.1 2%  
Cu 64 63.5 1%  
B 80 79.9 0%  
Pb 104 207 -99% factor of 2
I 124 127 -2%  
Hg 200 200.6 0%  

While quite a number of weights are close to the modern values, many are way out. However, the error is usually a stiotoimetric factor error.

From the HSM Database (Inventory no. 33732): SET OF WOODEN CUBES ILLUSTRATING ATOMIC WEIGHTS

Forty-two wooden cubes numbered 1-42, painted black with symbols for certain elements, compounds or radicals painted in white on the faces, together with the corresponding atomic, molecular or radical weights. The face markings appear in various combinations:

H C P Na Ca° S N K Fe K Na° Cy K°
1 6 16 24 28 16 14 40 28 48 32 26 48

A typical cube (no. 3) may be represented by the following figure. They present something of an enigma as their faces do not form an obvious pattern. The numbers indicate that there were 42 cubes. In style they are similar to the figures on the panel of atomic weights.

The cubes are listed in Daubeny's 1861 catalogue, p. 11 as: "Wooden cubes for illustrating atomic weight". [See D. R. Oldroyd, The Chemical Lectures at Oxford (1822-1854) of Charles Daubeny, M.D., F.R.S. Notes and Records of the Royal Society, vol. 33 (1979), pp. 217-259.]

This display was spotted by Eric Scerri who was visiting the museum with Mark Leach in 2010.

There is a virtual tour on the museum, and the above display is in the basement.

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Year:  1970 PT id = 885, Type = element

Discovery of Dubnium

Db

Dubnium, atomic number 105, has a mass of 268 au.

Synthetic radioactive element.

Dubnium was first observed in 1970 by A. Ghiorso et al. and V. A. Druin et al.

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Year:  1886 PT id = 846, Type = element

Discovery of Dysprosium

Dy

Dysprosium, atomic number 66, has a mass of 162.5 au.

Dysprosium was first isolated in 1886 by P.E.L. de Boisbaudran.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1952 PT id = 879, Type = element

Discovery of Einsteinium

Es

Einsteinium, atomic number 99, has a mass of 252 au.

Synthetic radioactive element.

Einsteinium was first observed in 1952 by A. Ghiorso et al.

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Year:  1955 PT id = 1086, Type = element misc data

Element Hunters

A YouTube video, The Element Hunters.

The text accompanying the video says:

"Scientist in Berkeley discover new elements [Californium & Einsteinium] from hydrogen bomb debris in 1951 and then use the 60 inch Cyclotron to create Mendelevium, element 101. The team included Nobel Prize winner Glenn Seaborg and famed element hunter, Albert Ghiorso."


Thanks to Roy Alexander for the tip! 

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Year:  2023 PT id = 1283, Type = data misc non-chem element

Element Names: The Etymology of The Periodic Table

An excellent video by RobWords about the names of the chemical elements and how they came about:

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Year:  1000 PT id = 472, Type = formulation element

Elements Known in the Year 1000

Elements known in the year 1000, taken from this Wikipedia page:

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Year:  1700 PT id = 473, Type = formulation element

Elements Known in the Year 1700

Elements known in the year 1700, taken from this Wikipedia page:

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Year:  1800 PT id = 235, Type = formulation element

Elements Known in the Year 1800

Elements known in the year 1800, taken from this Wikipedia page:

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Year:  1850 PT id = 474, Type = formulation element weight

Elements Known in the Year 1850

Elements known in the year 1850, taken from this Wikipedia page:

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Year:  1900 PT id = 236, Type = formulation element

Elements Known in the Year 1900

Elements known in the year 1900, taken from this Wikipedia page:

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Year:  1950 PT id = 475, Type = formulation element structure

Elements Known in the Year 1950

Elements known in the year 1950, taken from this Wikipedia page:

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Year:  2000 PT id = 476, Type = formulation element

Elements Known in the Year 2000

Elements known in the year 2000, taken from this Wikipedia page:

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Year:  2011 PT id = 477, Type = formulation element

Elements Known in the Year 2011

Elements known in the year 2011, taken from this Wikipedia page... all the elements to 118 are now known:

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Year:  1842 PT id = 848, Type = element

Discovery of Erbium

Er

Erbium, atomic number 68, has a mass of 167.259 au.

Erbium was first observed or predicted in 1842 by G. Mosander and first isolated in 1879 by T. Cleve.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1901 PT id = 843, Type = element

Discovery of Europium

Eu

Europium, atomic number 63, has a mass of 151.964 au.

Europium was first observed or predicted in 1896 by E.-A. Demarçay and first isolated in 1901 by E.-A. Demarçay.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1952 PT id = 880, Type = element

Discovery of Fermium

Fm

Fermium, atomic number 100, has a mass of 257 au.

Synthetic radioactive element.

Fermium was first observed in 1952 by A. Ghiorso et al.

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Year:  1999 PT id = 894, Type = element

Discovery of Flerovium

Fl

Flerovium, atomic number 114, has a mass of 289 au.

Synthetic radioactive element.

Flerovium was first observed in 1999 by Y. Oganessianet et al.

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Year:  1886 PT id = 798, Type = element

Discovery of Fluorine

F

Fluorine, atomic number 9, has a mass of 18.998 au.

Fluorine exists as a pale yellow diatomic molecular gas, F2. It is the most electronegative and reactive of all elements: it which reacts with practically all organic and inorganic substances.

Fluorine was first observed or predicted in 1810 by A.-M. Ampére and first isolated in 1886 by H. Moissan.

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Year:  1939 PT id = 867, Type = element

Discovery of Francium

Fr

Francium, atomic number 87, has a mass of 223 au.

Radioactive element.

Francium was first observed in 1939 by M. Perey.

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Year:  1880 PT id = 844, Type = element

Discovery of Gadolinium

Gd

Gadolinium, atomic number 64, has a mass of 157.25 au.

Gadolinium was first observed or predicted in 1880 by J. C. G. de Marignac and first isolated in 1886 by P.E.L. de Boisbaudran.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1875 PT id = 811, Type = element

Discovery of Gallium

Ga

Gallium, atomic number 31, has a mass of 69.723 au.

Gallium was first isolated in 1875 by P. E. L. de Boisbaudran.

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Year:  1886 PT id = 812, Type = element

Discovery of Germanium

Ge

Germanium, atomic number 32, has a mass of 72.63 au.

Germanium was first isolated in 1886 by C. A. Winkler.

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Year:  6000 BCE PT id = 859, Type = element

Discovery of Gold

Au

Gold, atomic number 79, has a mass of 196.967 au.

Gold had its earliest use in about 6000 BCE, and the oldest sample dates from 4400 BCE. It was discovered by Bulgaria and the earliest sample is from Varna Necropolis.

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Year:  1922 PT id = 852, Type = element

Discovery of Hafnium

Hf

Hafnium, atomic number 72, has a mass of 178.49 au.

Hafnium was first isolated in 1922 by D. Coster and G. von Hevesy.

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Year:  1984 PT id = 888, Type = element

Discovery of Hassium

Hs

Hassium, atomic number 108, has a mass of 270 au.

Synthetic radioactive element.

Hassium was first observed in 1984 by G. Münzenberg, P. Armbruster et al.

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Year:  1895 PT id = 782, Type = element

Discovery of Helium

He

Helium, atomic number 2, has a mass of 4.003 au.

Helium is a noble gas, and is the second most abundant element in the universe after hydrogen.

Helium was first observed or predicted in 1868 by P. Janssen and N. Lockyer from solar spectra, and first isolated in 1895 by W. Ramsay, T. Cleve, and N. Langlet.

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Year:  1900 PT id = 1284, Type = formulation data element review structure

History of the Discovery of the Group 18 (erstwhile Group 0) Elements

John Marks has provided a concise history of the discovery of the Group 18 elements and the element name"Nitron/Radon".

Radioactivity was discovered by Becquerel in 1896 and the Curies noted transferred radioactivity rather like the induction of electric or magnetic charge. Radon was discovered in 1900, by Dorn in Halle; Rutherford discovered thoron in 1899; and Debierne discovered actinon in 1903. The time-line is:

So niton (from Latin nitens = shining) was noticed by the Curies in 1899 as an emanation from radium. That same year Rutherford noted an identical emanation from thorium, and in 1903 Debierne discovered the same emanation from actinium. All three ('radon', 'thoron' and 'actinon') were identified as an element by Ramsay in 1904 and characterized by him in 1909.

Ramsay named the element niton after its most prominent property viz. that it glowed in the dark.

With the introduction of Soddy's isotopes, it became clear that: thoron was Nt-220, radon was Nt-222 & actinon was Nt-219.

There are natural traces of other isotopes (e.g. Nt-217, Nt-218) from beta disintegration of astatine. So "radon" was just one isotope of niton.

The foregoing history of niton is uncontroversial and the name niton, Nt, for Z = 86 dates at least from Professor Young´s textbook of stoichiometry in 1908.

In 1912, the name 'niton' was adopted by the International Commission for Atomic weights. Rydberg's PT of 1913 has Nt as the last inert gas, as does Irving Langmuir's PT of 1919, Niels Bohr's PT of 1922, GN Lewis's PT of 1923 and even the CRC's Handbook of Chemistry and Physics in 1924.

John Marks concludes:

"Niton, Nt, for Z = 86, was thus established by its discoverers and accepted by the chemistry (and physics) establishment. Radon, Rn, is an error perpetuated by IUPAC [amongst its many sins].

"Radon is an isotope. We do not refer to hydrogen as 'protium', so why are we referring to niton as 'radon'?"

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Year:  2021 PT id = 1217, Type = data element misc

History [of the] Elements and Periodic Table

From the Royal Society of Chemistry (RSC) an interactive Elements and Perioid Table History web page:

Thanks to Eric Scerri for the tip!

See the website EricScerri.com and Eric's Twitter Feed.

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Year:  1879 PT id = 847, Type = element

Discovery of Holmium

Ho

Holmium, atomic number 67, has a mass of 164.93 au.

Holmium was first observed or predicted in 1878 by J.-L. Soret and first isolated in 1879 by T. Cleve.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1766 PT id = 781, Type = element

Discovery of Hydrogen

H

Hydrogen, atomic number 1, has a mass of 1.008 au.

Hydrogen is the lightest element and by far the most abundant element in the universe: it makes up about about 90% of the universe by weight. Under standard conditions, hydrogen exists as a diatomic molecular gas, H2.

Hydrogen was first isolated and identified as an element in 1766 by H. Cavendish, although it was first made in 1500 by Paracelsus.

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Year:  1863 PT id = 829, Type = element

Discovery of Indium

In

Indium, atomic number 49, has a mass of 114.818 au.

Indium was first observed or predicted in 1863 by F. Reich and T. Richter and first isolated in 1867 by T. Richter.

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Year:  1811 PT id = 833, Type = element

Discovery of Iodine

I

Iodine, atomic number 53, has a mass of 126.904 au.

Iodine exists as a black diatomic molecular solid, I2.

Iodine was first isolated in 1811 by B. Courtois.

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Year:  1803 PT id = 857, Type = element

Discovery of Iridium

Ir

Iridium, atomic number 77, has a mass of 192.217 au.

Iridium was first isolated in 1803 by S. Tennant.

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Year:  5000 BCE PT id = 806, Type = element

Discovery of Iron

Fe

Iron, atomic number 26, has a mass of 55.845 au.

Iron had its earliest use in about 5000 BCE, and the oldest sample dates from 4000 BCE from Egypt.

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Year:  1898 PT id = 816, Type = element

Discovery of Krypton

Kr

Krypton, atomic number 36, has a mass of 83.798 au.

Krypton is a noble gas.

Krypton was first isolated in 1898 by W. Ramsay and W. Travers.

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Year:  1838 PT id = 837, Type = element

Discovery of Lanthanum

La

Lanthanum, atomic number 57, has a mass of 138.905 au.

Lanthanum was first observed or predicted in 1838 by G. Mosander and first isolated in 1841 by G. Mosander.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1961 PT id = 883, Type = element

Discovery of Lawrencium

Lr

Lawrencium, atomic number 103, has a mass of 262 au.

Synthetic radioactive element.

Lawrencium was first observed in 1961 by A. Ghiorso, T. Sikkeland, E. Larsh and M. Latimer.

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Year:  7000 BCE PT id = 862, Type = element

Discovery of Lead

Pb

Lead, atomic number 82, has a mass of 207.2 au.

Lead had its earliest use in about 7000 BCE, and the oldest sample dates from 3800 BCE. It was discovered by Africa and the earliest sample is from Abydos, Egypt.

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Year:  1817 PT id = 783, Type = element

Discovery of Lithium

Li

Lithium, atomic number 3, has a mass of 6.968 au.

Lithium is a reactive metal, of low density: it is the least dense metal.

Lithium was first observed or predicted in 1817 by A. Arfwedson and first isolated in 1821 by W. T. Brande.

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Year:  2000 PT id = 896, Type = element

Discovery of Livermorium

Lv

Livermorium, atomic number 116, has a mass of 293 au.

Synthetic radioactive element.

Livermorium was first observed in 2000 by Y. Oganessian et al.

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Year:  1906 PT id = 851, Type = element

Discovery of Lutetium

Lu

Lutetium, atomic number 71, has a mass of 174.967 au.

Lutetium was first isolated in 1906 by C. A. von Welsbach and G. Urbain.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1808 PT id = 791, Type = element

Discovery of Magnesium

Mg

Magnesium, atomic number 12, has a mass of 24.306 au.

Magnesium is a Group 2 element, and these are called: "alkaline earth metals".

Magnesium was first observed or predicted in 1755 by J. Black and first isolated in 1808 by H. Davy.

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Year:  1774 PT id = 805, Type = element

Discovery of Manganese

Mn

Manganese, atomic number 25, has a mass of 54.938 au.

Manganese was first observed or predicted in 1774 by W. Scheele and first isolated in 1774 by G. Gahn.

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Year:  1982 PT id = 889, Type = element

Discovery of Meitnerium

Mt

Meitnerium, atomic number 109, has a mass of 276 au.

Synthetic radioactive element.

Meitnerium was first observed in 1982 by G. Münzenberg, P. Armbrusteret al.

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Year:  1955 PT id = 881, Type = element

Discovery of Mendelevium

Md

Mendelevium, atomic number 101, has a mass of 258 au.

Synthetic radioactive element.

Mendelevium was first observed in 1955 by A. Ghiorso, G. Harvey, R. Choppin, S. G. Thompson and G. T. Seaborg.

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Year:  2000 BCE PT id = 860, Type = element

Discovery of Mercury

Hg

Mercury, atomic number 80, has a mass of 200.592 au.

Mercury had its earliest use in about 2000 BCE, and the oldest sample dates from 1500 BCE. It was discovered by Chinese/Indians and the earliest sample is from Egypt.

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Year:  1781 PT id = 822, Type = element

Discovery of Molybdenum

Mo

Molybdenum, atomic number 42, has a mass of 95.95 au.

Molybdenum was first observed or predicted in 1778 by W. Scheele and first isolated in 1781 by J. Hjelm.

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Year:  2003 PT id = 895, Type = element

Discovery of Moscovium

Mc

Moscovium, atomic number 115, has a mass of 288 au.

Synthetic radioactive element.

Moscovium was first observed in 2003 by Y. Oganessian et al.

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Year:  1913 PT id = 13, Type = formulation element structure

Moseley's Periodic Law and Atomic Number Z

Moseley, H. G. J. The High-Frequency Spectra of the Elements. Philosophical Magazine, 26, 1024–1034 (1913).

Wikipedia:

"Moseley's law is an empirical law concerning the characteristic X-rays emitted by atoms. The law was discovered and published by the English physicist Henry Moseley in 1913–1914. Until Moseley's work, "atomic number" was merely an element's place in the periodic table and was not known to be associated with any measurable physical quantity.

"In brief, Moseley's law states that the square root of the frequency, ν, of the emitted X-ray is (approximately) proportional to the atomic number":

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Year:  1885 PT id = 840, Type = element

Discovery of Neodymium

Nd

Neodymium, atomic number 60, has a mass of 144.242 au.

Neodymium was first isolated in 1885 by Carl Auer von Welsbach.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1898 PT id = 789, Type = element

Discovery of Neon

Ne

Neon, atomic number 10, has a mass of 20.18 au.

Neon is a noble gas. It is present in the atmosphere, 1 part in 65000.

Neon was first isolated in 1898 by W. Ramsay and W. Travers.

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Year:  1940 PT id = 873, Type = element

Discovery of Neptunium

Np

Neptunium, atomic number 93, has a mass of 237 au.

Radioactive element: Np is only found in tiny amounts in nature. Most samples are synthetic.

Neptunium was first observed in 1940 by E.M. McMillan and H. Abelson.

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Year:  1751 PT id = 808, Type = element

Discovery of Nickel

Ni

Nickel, atomic number 28, has a mass of 58.693 au.

Nickel was first isolated in 1751 by F. Cronstedt.

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Year:  2003 PT id = 893, Type = element

Discovery of Nihonium

Nh

Nihonium, atomic number 113, has a mass of 284 au.

Synthetic radioactive element.

Nihonium was first observed in 2003 by Y. Oganessian et al. and K. Morita et al.

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Year:  1801 PT id = 821, Type = element

Discovery of Niobium

Nb

Niobium, atomic number 41, has a mass of 92.906 au.

Niobium was first observed or predicted in 1801 by C. Hatchett and first isolated in 1864 by W. Blomstrand.

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Year:  1772 PT id = 787, Type = element

Discovery of Nitrogen

N

Nitrogen, atomic number 7, has a mass of 14.007 au.

Nitrogen exists as a diatomic molecular gas, N2, and in this form it makes up about 78% of the atmosphere by volume. The element seemed so inert that Lavoisier named it azote, meaning "without life".

Nitrogen was first isolated in 1772 by D. Rutherford.

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Year:  1966 PT id = 882, Type = element

Discovery of Nobelium

No

Nobelium, atomic number 102, has a mass of 259 au.

Synthetic radioactive element.

Nobelium was first observed in 1966 by E. D. Donets, V. A. Shchegolev and V. A. Ermakov.

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Year:  2002 PT id = 898, Type = element

Discovery of Oganesson

Og

Oganesson, atomic number 118, has a mass of 294 au.

Synthetic radioactive element.

Oganesson was first observed in 2002 by Y. Oganessian et al.

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Year:  1803 PT id = 856, Type = element

Discovery of Osmium

Os

Osmium, atomic number 76, has a mass of 190.23 au.

Osmium was first isolated in 1803 by S. Tennant.

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Year:  1771 PT id = 788, Type = element

Discovery of Oxygen

O

Oxygen, atomic number 8, has a mass of 15.999 au.

Oxygen exists as a diatomic molecular gas, O2; in this form it makes up about 20% of the atmosphere.

Oxygen was first isolated in 1771 by W. Scheele.

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Year:  1803 PT id = 826, Type = element

Discovery of Palladium

Pd

Palladium, atomic number 46, has a mass of 106.42 au.

Palladium was first isolated in 1803 by H. Wollaston.

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Year:  2019 PT id = 1246, Type = misc element

Periodic Table of the Elements Coloring Book

Periodic Table of the Elements Coloring Book

Project managing and chemistry overseen by Yann Brouillette (Faculty, Chemistry, Dawson College). Element representations and cover by Dawson College Illustration & Design students (2nd year)* overseen by Meinert Hansen (Faculty, Illustration & Design, Dawson College).


Thanks to René for the tip!

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Year:  1669 PT id = 794, Type = element

Discovery of Phosphorus

P

Phosphorus, atomic number 15, has a mass of 30.974 au.

Phosphorus exists in several allotropic forms including: white, red and black.

Phosphorus was first isolated in 1669 by H. Brand.

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Year:  1748 PT id = 858, Type = element

Discovery of Platinum

Pt

Platinum, atomic number 78, has a mass of 195.084 au.

Platinum was first isolated in 1748 by A. de Ulloa, although it had been used by pre-Colombian Americans.

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Year:  1940 PT id = 874, Type = element

Discovery of Plutonium

Pu

Plutonium, atomic number 94, has a mass of 244 au.

Radioactive element: Pu is only found in tiny amounts in nature. Most samples are synthetic.

Plutonium was first observed in 1940 by Glenn T. Seaborg, Arthur C. Wahl, W. Kennedy and E.M. McMillan.

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Year:  1898 PT id = 864, Type = element

Discovery of Polonium

Po

Polonium, atomic number 84, has a mass of 209 au.

Radioactive element.

Polonium was first observed or predicted in 1898 by P. and M. Curie and first isolated in 1902 by W. Marckwald.

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Year:  1807 PT id = 799, Type = element

Discovery of Potassium

K

Potassium, atomic number 19, has a mass of 39.098 au.

Potassium is a Group 1 element, and these are often referred to as the "alkali metals".

Potassium was first isolated in 1807 by H. Davy.

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Year:  1885 PT id = 839, Type = element

Discovery of Praseodymium

Pr

Praseodymium, atomic number 59, has a mass of 140.908 au.

Praseodymium was first isolated in 1885 by Carl Auer von Welsbach.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1945 PT id = 841, Type = element

Discovery of Promethium

Pm

Promethium, atomic number 61, has a mass of 145 au.

Radioactive element: Pm is only found in tiny amounts in nature. Most samples are synthetic.

Promethium was first observed or predicted in 1942 by S. Wu, E.G. Segrè and H. Bethe and first isolated in 1945 by Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin, and Harold G. Richter.

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Year:  1913 PT id = 871, Type = element

Discovery of Protactinium

Pa

Protactinium, atomic number 91, has a mass of 231.036 au.

Radioactive element: Pa is only found in tiny amounts in nature. Most samples are synthetic.

Protactinium was first observed or predicted in 1913 by O. H. Göhring and K. Fajans and first isolated in 1927 by A. von Grosse.

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Year:  1898 PT id = 868, Type = element

Discovery of Radium

Ra

Radium, atomic number 88, has a mass of 226 au.

Radioactive element.

Radium was first observed or predicted in 1898 by P. and M. Curie and first isolated in 1902 by M. Curie.

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Year:  1899 PT id = 866, Type = element

Discovery of Radon

Rn

Radon, atomic number 86, has a mass of 222 au.

Radon is a noble gas and it is a radioactive element.

Radon was first observed or predicted in 1899 by E. Rutherford and R. B. Owens and first isolated in 1910 by W. Ramsay and R. Whytlaw-Gray.

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Year:  1919 PT id = 855, Type = element

Discovery of Rhenium

Re

Rhenium, atomic number 75, has a mass of 186.207 au.

Rhenium was first observed or predicted in 1908 by M. Ogawa and first isolated in 1919 by M. Ogawa.

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Year:  1804 PT id = 825, Type = element

Discovery of Rhodium

Rh

Rhodium, atomic number 45, has a mass of 102.906 au.

Rhodium was first isolated in 1804 by H. Wollaston.

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Year:  1994 PT id = 891, Type = element

Discovery of Roentgenium

Rg

Roentgentium, atomic number 111, has a mass of 280 au.

Synthetic radioactive element.

Roentgenium was first observed in 1994 by S. Hofmann et al.

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Year:  1861 PT id = 817, Type = element

Discovery of Rubidium

Rb

Rubidium, atomic number 37, has a mass of 85.468 au.

Rubidium is a Group 1 element, and these are often referred to as the "alkali metals".

Rubidium was first observed, but not isolated in pure form, in 1861 by R. Bunsen and G. R. Kirchhoff.

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Year:  1844 PT id = 824, Type = element

Discovery of Ruthenium

Ru

Ruthenium, atomic number 44, has a mass of 101.07 au.

Ruthenium was first isolated in 1844 by K. Claus.

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Year:  1969 PT id = 884, Type = element

Discovery of Rutherfordium

Rf

Rutherfordium, atomic number 104, has a mass of 267 au.

Synthetic radioactive element.

Rutherfordium was first observed in 1969 by A. Ghiorso et al. and I. Zvara et al.

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Year:  1879 PT id = 842, Type = element

Discovery of Samarium

Sm

Samarium, atomic number 62, has a mass of 150.36 au.

Samarium was first isolated in 1879 by P.E.L. de Boisbaudran.

Chronology of chemically the splitting of ceria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1879 PT id = 801, Type = element

Discovery of Scandium

Sc

Scandium, atomic number 21, has a mass of 44.956 au.

Scandium was first isolated in 1879 by F. Nilson.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1974 PT id = 886, Type = element

Discovery of Seaborgium

Sg

Seaborgium, atomic number 106, has a mass of 271 au.

Synthetic radioactive element.

Seaborgium was first observed in 1974 by A. Ghiorso et al.

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Year:  1817 PT id = 814, Type = element

Discovery of Selenium

Se

Selenium, atomic number 34, has a mass of 78.971 au.

Selenium was first isolated in 1817 by J. Berzelius and G. Gahn.

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Year:  2023 PT id = 1287, Type = formulation element data misc spiral

Semicircular Hybrid Chart of the Nuclides

Nawa Nagayasu has produced a new version of the Segrè Chart of the Nuclides.

Nawa writes:

"The chart has the number of neutrons on the [curved] horizontal axis and the number of protons (atomic number) on the vertical axis. I used the IAEA colour coding [scheme]. JAEA's half-life ranks are indicated by simple numbers, not rounded frames.

"In order to fit the whole chart into a semicircle, the axis representing the number of neutrons was made a spiral-like curve. For clarity, the number of neutrons is shown in the middle of each curve."

Yuri Oganessian has commented:

"Nawa Nagayasu is an original and talented designer. After all, it is not easy to work with 118 elements, but now also with isotopes, of which there are more than 3000. The fan design looks attractive and this is very important. This will make people, especially school age, guess the numbers that are written there. So they will gradually delve into the content of the Table, a truly brilliant creation."

Click image to enlarge

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Year:  1824 PT id = 793, Type = element

Discovery of Silicon

Si

Silicon, atomic number 14, has a mass of 28.085 au.

Silicon makes up 25.7% of the earth's crust, and after oxygen is the second most abundant element.

Silicon was first isolated in 1823 by J. Berzelius.

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Year:  5000 BCE PT id = 827, Type = element

Discovery of Silver

Ag

Silver, atomic number 47, has a mass of 107.868 au.

Silver had its earliest use in about 5000 BCE, and the oldest sample dates from 4000 BCE, and is from Asia Minor.

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Year:  1807 PT id = 790, Type = element

Discovery of Sodium

Na

Sodium, atomic number 11, has a mass of 22.99 au.

Sodium is a Group 1 element, and these are often referred to as the "alkali metals".

Sodium was first isolated in 1807 by H. Davy.

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Year:  1808 PT id = 818, Type = element

Discovery of Strontium

Sr

Strontium, atomic number 38, has a mass of 87.62 au.

Strontium is a Group 2 element, and these are called: "alkaline earth metals".

Strontium was first observed or predicted in 1787 by W. Cruikshank and first isolated in 1808 by H. Davy.

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Year:  2000 BCE PT id = 795, Type = element

Discovery of Sulfur (Sulphur)

S

Sulfur, atomic number 16, has a mass of 32.068 au.

Sulfur is a pale yellow, odourless, brittle solid.

Sulfur had its earliest use in about 2000 BCE. It was discovered by Chinese/Indians.

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Year:  1802 PT id = 853, Type = element

Discovery of Tantalum

Ta

Tantalum, atomic number 73, has a mass of 180.948 au.

Tantalum was first isolated in 1802 by G. Ekeberg.

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Year:  1937 PT id = 823, Type = element

Discovery of Technetium

Tc

Technetium, atomic number 43, has a mass of 98 au.

Radioactive element: Tc is only found in tiny amounts in nature. Most samples are synthetic.

Technetium was first isolated in 1937 by C. Perrier and E. Segrè. The element had been predicted by Mendeleev in 1871 as eka-manganese.

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Year:  1782 PT id = 832, Type = element

Discovery of Tellurium

Te

Tellurium, atomic number 52, has a mass of 127.6 au.

Tellurium caused great difficulty to the chemists who first tried to develop a periodic table, because it has an atomic weight greater than iodine (126.9). Mendeleev prioritised chemical properties over the anomalous atomic weight data, and correctly classified Te along with O, S, & Se. It was only when nuclear structure and the importance of atomic number was recognised, around 1918, that the issue was explained.

Tellurium was first isolated in 1782 by F.-J.M. von Reichenstein.

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Year:  2010 PT id = 897, Type = element

Discovery of Tennessine

Ts

Tennessine, atomic number 117, has a mass of 292 au.

Synthetic radioactive element.

Tennessine was first observed in 2010 by Y. Oganessian et al.

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Year:  1842 PT id = 845, Type = element

Discovery of Terbium

Tb

Terbium, atomic number 65, has a mass of 158.925 au.

Terbium was first observed or predicted in 1842 by G. Mosander and first isolated in 1886 by J.C.G. de Marignac.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1861 PT id = 861, Type = element

Discovery of Thallium

Tl

Thallium, atomic number 81, has a mass of 204.384 au.

Thallium was first observed or predicted in 1861 by W. Crookes and first isolated in 1862 by C.-A. Lamy.

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Year:  1907 PT id = 1332, Type = formulation review element

Thompson's Electron Rings

After proposing, what became known as the plump-puddding model of the atom in 1904, J.J. Thompson developed the idea in his book The Corpuscular Theory of Matter, Archibale Constable, 1907(available as a scanned document online).

Thompson's Electron Rings are sumarised in this table:

The origional text reads (taken from pages 104-110). Note, for "corpusle" read "electron":




Thanks to Eric Scerri for the tip.

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Year:  1829 PT id = 870, Type = element

Discovery of Thorium

Th

Thorium, atomic number 90, has a mass of 232.038 au.

Radioactive element with a very long half-life.

Thorium was first observed or predicted in 1829 by J. Berzelius and first isolated in 1914 by D. Lely, Jr. and L. Hamburger.

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Year:  1879 PT id = 849, Type = element

Discovery of Thulium

Tm

Thulium, atomic number 69, has a mass of 168.934 au.

Thulium was first isolated in 1879 by T. Cleve.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  3500 BCE PT id = 830, Type = element

Discovery of Tin

Sn

Tin, atomic number 50, has a mass of 118.71 au.

Tin + copper gives bronze, and so the Bronze Age.

Tin had its earliest use in about 3500 BCE, and the oldest sample dates from 2000 BCE. It is unknown who discovered the element.

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Year:  1791 PT id = 802, Type = element

Discovery of Titanium

Ti

Titanium, atomic number 22, has a mass of 47.867 au.

Titanium was first observed or predicted in 1791 by W. Gregor and first isolated in 1825 by J. Berzelius.

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Year:  1783 PT id = 854, Type = element

Discovery of Tungsten

W

Tungsten, atomic number 74, has a mass of 183.84 au.

Tungsten was first observed or predicted in 1781 by W. Scheele and first isolated in 1783 by J. and F. Elhuyar.

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Year:  1789 PT id = 872, Type = element

Discovery of Uranium

U

Uranium, atomic number 92, has a mass of 238.029 au.

Radioactive element with a very long half-life.

Uranium was first observed or predicted in 1789 by H. Klaproth and first isolated in 1841 by E.-M. Péligot.

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Year:  1830 PT id = 803, Type = element

Discovery of Vanadium

V

Vanadium, atomic number 23, has a mass of 50.942 au.

Vanadium was first observed or predicted in 1801 by M. del Río and first isolated in 1830 by N.G.Sefström.

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Year:  2022 PT id = 1236, Type = data misc element

Which Element is the Best?

The That Chemist YouTube channel asks "Which Element is the Best? Elements 1-20 & Elements 21-40"

That Chemist is a synthetic organic chemist and his bias is in that direction although he gives a variety of examples:


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Year:  1813 PT id = 1044, Type = formulation element weight

Wollaston's Synoptic Scale of Chemical Equivalents

Philosophical Transactions: A Synoptic Scale of Chemical Equivalents by William Hyde Wollaston, M.D. Sec. R.S., or from here.

It is apparent that chemistry the years 1810 to 1850 was largely concerned with discovering the whole number stoichiometric ratios of atoms in chemical compounds.

Wollaston writes in the text above:

"It is impossible in several instances, where only two combinations of the same ingredients are known, to discover which of the compounds is to be regarded as consisting of a pair of single atoms, and since the decision of these questions is purely theoretical, and by no means necessary to the formation of a table adapted to most practical purposes, I have not been desirous of warping my numbers according to an atomic theory, but have endeavored to make practical convenience my sole guide, and have considered the doctrine of simple multiples, on which that of atoms is founded, merely as a valuable assistant in determining, by simple division, the amount of those quantities that are liable to such definite deviations from the original law of Richter."

"Mr. Dalton in his atomic views of chemical combination appears not to have taken much pains to ascertain the actual prevalence of that law of multiple proportions by which the atomic theory is best supported [however] it is in fact to Mr. Dalton that we are indebted for the first correct observation of such an instance of a simple multiple in the union of nitrous gas with oxygen."

"[I have] computed a series of supposed atoms, I [have] assumed oxygen as the decimal unit of my scale [ie. oxygen = 10], in order to facilitate the estimation of those numerous combinations which it forms with other bodies. Though the present table of Equivalents, I have taken care to make oxygen equally prominent on account of the important part it performs in determining the affinities of bodies by the different proportions in which it is united to them.."

Mark Leach writes:

"When Wollaston's equivalent weights are converted from O = 10.00 to the modern value of O = 15.999, the atomic weight values can be seen to be astonishingly accurate.

"However, the language of the article is quite difficult as the meaning of many of the terms is unclear (to me, at least). For example, in modern usage adding 'ia' to a metal implies the oxide: 'magnesia' is magnesium oxide, MgO. I am not clear if this historical usage is consistent. 'Azote' is nitrogen and 'muriatic acid (dry)' is hydrogen chloride gas. I have only analyses/re-calculated the elements and a couple of common/obvious compounds:"

  Wollaston's data Scaled to O = 15.999 Modern Values % error
H (as H2) 1.32 2.112 2.016 5%
O 10.00 15.999 15.999 ref. value
H2O 11.32 18.111 18.015 1%
C 7.74 12.383 12.011 3%
S 20.00 31.998 32.060 0%
P 17.40 27.838 30.974 -11%
N (as N2) 17.54 28.062 28.014 0%
Cl (as Cl2) 44.10 70.556 70.900 0%
Fe 34.50 55.197 55.845 -1%
Cu 40.00 63.996 63.546 1%
Zn 41.00 65.596 65.380 0%
Hg 125.50 200.787 200.590 0%
Pb 129.50 207.187 207.980 0%
Ag 135.00 215.987 107.870 50%

Interestingly, Wollaston's analysis is far better than Daubeny's 1831 data seen in Oxford.

Read more in an entry concerning chemical slide rules.

Thanks to Nawa for the tip!

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Year:  1898 PT id = 834, Type = element

Discovery of Xenon

Xe

Xenon, atomic number 54, has a mass of 131.293 au.

Xenon is a noble gas.

Xenon was first isolated in 1898 by W. Ramsay and W. Travers.

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Year:  1878 PT id = 850, Type = element

Discovery of Ytterbium

Yb

Ytterbium, atomic number 70, has a mass of 173.054 au.

Ytterbium was first observed or predicted in 1878 by J.C.G. de Marignac and first isolated in 1906 by C. A. von Welsbach.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1794 PT id = 819, Type = element

Discovery of Yttrium

Y

Yttrium, atomic number 39, has a mass of 88.906 au.

Yttrium was first observed or predicted in 1794 by J. Gadolin and first isolated in 1842 by G. Mosander.

Chronology of chemically the splitting of yttria (mixed oxides) into the pure rare-earth metals:

From: CRC Handbook on the Physics and Chemistry of Rare Earths, Chapter 248. Accommodation of the Rare Earths in the Periodic Table: A Historical Analysis
by Pieter Thyssen and Koen Binnemans (ISBN: 978-0-444-53590-0)

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Year:  1000 BCE PT id = 810, Type = element

Discovery of Zinc

Zn

Zinc, atomic number 30, has a mass of 65.38 au.

Zinc had its earliest use in about 1000 BCE, and the oldest sample dates from 1000 BCE. It was discovered by Indian metallurgists and the earliest sample is from the Indian subcontinent.

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Year:  1789 PT id = 820, Type = element

Discovery of Zirconium

Zr

Zirconium, atomic number 40, has a mass of 91.224 au.

Zirconium was first observed or predicted in 1789 by H. Klaproth and first isolated in 1824 by J. Berzelius.

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© Mark R. Leach Ph.D. 1999 –

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